/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.read.biff;

import jxl.CellType;
import jxl.ErrorCell;
import jxl.ErrorFormulaCell;
import jxl.biff.FormattingRecords;
import jxl.biff.FormulaData;
import jxl.biff.WorkbookMethods;
import jxl.biff.formula.ExternalSheet;
import jxl.biff.formula.FormulaErrorCode;
import jxl.biff.formula.FormulaException;
import jxl.biff.formula.FormulaParser;
import jxl.common.Assert;

/**
 * An error resulting from the calculation of a formula
 */
class ErrorFormulaRecord extends CellValue
        implements ErrorCell, FormulaData, ErrorFormulaCell {
    /**
     * The error code of this cell
     */
    private int errorCode;

    /**
     * A handle to the class needed to access external sheets
     */
    private ExternalSheet externalSheet;

    /**
     * A handle to the name table
     */
    private WorkbookMethods nameTable;

    /**
     * The formula as an excel string
     */
    private String formulaString;

    /**
     * The raw data
     */
    private byte[] data;

    /**
     * The error code
     */
    private FormulaErrorCode error;

    /**
     * Constructs this object from the raw data
     *
     * @param t the raw data
     * @param fr the formatting records
     * @param es the external sheet
     * @param nt the name table
     * @param si the sheet
     */
    public ErrorFormulaRecord(Record t, FormattingRecords fr, ExternalSheet es,
                              WorkbookMethods nt,
                              SheetImpl si) {
        super(t, fr, si);

        externalSheet = es;
        nameTable = nt;
        data = getRecord().getData();

        Assert.verify(data[6] == 2);

        errorCode = data[8];
    }

    /**
     * Interface method which gets the error code for this cell.  If this cell
     * does not represent an error, then it returns 0.  Always use the
     * method isError() to  determine this prior to calling this method
     *
     * @return the error code if this cell contains an error, 0 otherwise
     */
    public int getErrorCode() {
        return errorCode;
    }

    /**
     * Returns the numerical value as a string
     *
     * @return The numerical value of the formula as a string
     */
    public String getContents() {
        if (error == null) {
            error = FormulaErrorCode.getErrorCode(errorCode);
        }

        return error != FormulaErrorCode.UNKNOWN ?
                error.getDescription() : "ERROR " + errorCode;
    }

    /**
     * Returns the cell type
     *
     * @return The cell type
     */
    public CellType getType() {
        return CellType.FORMULA_ERROR;
    }

    /**
     * Gets the raw bytes for the formula.  This will include the
     * parsed tokens array
     *
     * @return the raw record data
     */
    public byte[] getFormulaData() throws FormulaException {
        if (!getSheet().getWorkbookBof().isBiff8()) {
            throw new FormulaException(FormulaException.BIFF8_SUPPORTED);
        }

        // Lop off the standard information
        byte[] d = new byte[data.length - 6];
        System.arraycopy(data, 6, d, 0, data.length - 6);

        return d;
    }

    /**
     * Gets the formula as an excel string
     *
     * @return the formula as an excel string
     * @exception FormulaException
     */
    public String getFormula() throws FormulaException {
        if (formulaString == null) {
            byte[] tokens = new byte[data.length - 22];
            System.arraycopy(data, 22, tokens, 0, tokens.length);
            FormulaParser fp = new FormulaParser
                    (tokens, this, externalSheet, nameTable,
                            getSheet().getWorkbook().getSettings());
            fp.parse();
            formulaString = fp.getFormula();
        }

        return formulaString;
    }
}

